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Genuine GM parts have one of these marks:

Vehicle Care
California Proposition 65 WarningRear Side Door Trim Replacement
Rear Side Door Inside Handle Bolt Finish Cap
Procedure
Pull handle back to remove cap. Use suitable tool to unsnap.
Rear Side Door Inside Handle Screw
Caution: Refer to Fastener Caution in the Preface section.
Tighten
2.5 N·m (23 lb in)
Rear Side Door Pull Handle Screw
T ...
Removal Procedure
Warning: Refer to Approved Equipment for Collision Repair Warning in the
Preface section.
Warning: Refer to Glass and Sheet Metal Handling Warning in the Preface section.
Disable the SIR System. Refer to SIR Disabling and Enabling
Disconnect the negative battery cable. Refer to Batte ...
Installation Procedure
Align the rear compartment floor panel.
Drill 8 mm (5/16 in) for plug welding along the edges of the rear compartment
floor panel as noted from the original panel.
Clean and prepare the attaching surfaces for
welding.
Position the rear compartment floor panel on the vehicle.
V ...